In Reply: The look-back study performed by
Dr Cooling provides additional support for the policy of permanent deferral
of blood donors who have been directly implicated in a TRALI reaction. The
study also supports our conclusion that TRALI is underrecognized and underreported.

Although the incidence of TRALI in the 2 look-back studies was 15% and
36%, this should not be confused with the overall incidence of TRALI. The
donors in both look-back studies possessed antibodies to white blood cells.
It should not be assumed that the incidence of TRALI reactions from the transfusion
of blood components without such antibodies would be similar. Studies examining
all cases of acute respiratory distress associated with transfusion, at a
single hospital, suggest the rate of TRALI is about 1 per 5000 transfusions
or 1 per 2000 patients transfused.1,2
These studies, however, do not include milder forms of TRALI without acute
respiratory distress and thus may underestimate the incidence of TRALI.